The Thermal Decomposition of Propyl Mercaptan

The thermal decomposition of normal propyl mercaptan over a temperature range from 405 to 435°C and pressures from 100 to 300 mm is homogeneous on a poisoned glass surface. The reaction is complex showing an induction period with auto-accelerating rate, ending finally in a pseudo-equilibrium involving propylene, hydrogen sulphide and isopropyl mercaptan. The energy of activation of the induction period is about 40,000 calories and that of the later reaction 39,000 calories. A mechanism, has been proposed which involves primarily the formation of propyl sulphide reacting further to form a sulphonium hydrosulphide as an unstable intermediate.